1. Field of the Invention
The invention relates to the art of forming unitary concrete shell structures suitable for use in housing and the like. Particularly, the invention relates to an apparatus and method of forming an integral concrete shell in a rotatable form in which each of the structural portions of the shell such as sides, top and bottom is formed progressively by pouring and finishing the concrete for each portion when it is positioned in a substantially horizontal position.
2. Description of the Prior Art
The prior art is replete with examples of various efforts to mass produce housing units of concrete such as is represented by U.S. Pat. Nos. 3,558,095; 3,853,452; 3,993,720; 4,426,060; and 4,828,217 as well as prior art patent 3,932,082 issued to the present inventor. Among this prior art the inventor's patent, U.S. Pat. No. 3,932,082, provides a means for making a reinforced concrete module suitable for use as a housing structure in which the walls, as well as the top and bottom are formed in a substantially horizontal position. The other references employ typically moveable forms for forming the walls between inner and outer vertical forms which are cumbersome and require substantial additional structure and labor for positioning the forms relative to each other preparatory to receiving the concrete and for subsequently removing the forms after the concrete has set up or, the prior art requires that a series of flat slabs be secured together to form a box-like structure. The prior art patent of the inventor discloses an apparatus for rotating a cage-like structure of reinforcement material, but even it suffers from the disadvantage of having to pick up the entire assembly in order to rotate it so as to position the various sides in a horizontal position for receiving the concrete.